Submission #1255059

#	Time	Username	Problem	Language	Result	Execution time	Memory
1255059		VMaksimoski008	Synchronization (JOI13_synchronization)	C++20	100 / 100	266 ms	22428 KiB

synchronization

#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;

struct fenwick {
    int n;
    vector<int> tree;

    fenwick(int _n) : n(_n+10), tree(n+10) {}

    void update(int p, int v) {
        for(p++; p<n; p+=p&-p) tree[p] += v;
    }

    int query(int p) {
        int ans = 0;
        for(p++; p; p-=p&-p) ans += tree[p];
        return ans;
    }
} fwt(2*N);

vector<int> g[N];
int n, m, q, in[N], out[N], timer = 1, up[N][20], A[N], B[N], vis[N], a[N], c[N];

void dfs(int u, int p) {
    up[u][0] = p;
    in[u] = timer++;
    for(int i=1; i<20; i++) 
        up[u][i] = up[ up[u][i-1] ][i-1];

    for(int v : g[u]) if(v ^ p) {
        dfs(v, u);
    }

    out[u] = timer++;
}

int root(int u) {
    for(int i=19; i>=0; i--) {
        if(!up[u][i]) continue;
        if(fwt.query(in[u]) == fwt.query(in[ up[u][i] ])) 
            u = up[u][i];
    }
    return u;
}

signed main() {
    ios_base::sync_with_stdio(false);
    cout.tie(0); cin.tie(0);

    cin >> n >> m >> q;
    for(int i=1; i<n; i++) {
        cin >> A[i] >> B[i];
        g[A[i]].push_back(B[i]);
        g[B[i]].push_back(A[i]);
    }

    dfs(1, 1);
    for(int i=1; i<=n; i++) a[i] = 1;

    for(int i=1; i<n; i++) {
        if(in[A[i]] > in[B[i]]) swap(A[i], B[i]);
        fwt.update(in[B[i]], 1);
        fwt.update(out[B[i]], -1);
    }

    while(m--) {
        int id; cin >> id;
        int u = B[id];

        int val = !vis[id] ? -1 : 1;
        fwt.update(in[u], val);
        fwt.update(out[u], -val);

        if(!vis[id]) {
            int v = root(A[id]);
            a[v] += a[u] - c[u];
            c[u] = a[u];
        } else {
            int v = root(A[id]);
            a[u] = c[u] = a[v];
        }

        vis[id] ^= 1;
    }
    
    while(q--) {
        int u; cin >> u;
        cout << a[root(u)] << '\n';
    }
}

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 10 / 10
• Subtask 4: 20 / 20
• Subtask 5: 40 / 40